Do you know this about hot air balloons?

　　The International Aviation Federation once listed hot air balloons as the safest aircraft.

　　Let's start from all angles today

　　Understand how hot air balloons do it?

　　The only flying force of a hot air balloon is the wind. For hot air balloons flying around the world, high air flows with appropriate speed and direction must be selected and moved accordingly to complete the flight efficiently. Just like when traveling around the world, hot air balloons need to ride on different airflows. When "air change flow", what the pilot needs to adjust the height. The height of the hot air balloon usually reaches more than ten thousand meters.

　　From the data alone,

　　The safety factor of hot air balloons is also quite high.

　　So what are the specific technical requirements?

　　Strict flight conditions for hot air balloons

　　Because the hot air balloon itself does not have a power system, the speed or slowness of the hot air balloon is determined by the speed of the wind. The best time for hot air balloons to fly just after the sun rises or one or two hours before the sun sets, because the wind is usually very calm and the airflow is stable. Strong winds and heavy fog are not conducive to the flight of hot air balloons. According to regulations, only if the wind speed is less than 6 meters/sec, the visibility is greater than 1.5 kilometers, and there is no large precipitation in the flying airspace can you fly freely.

　　Strict and exquisite equipment for hot air balloons

　　The hot air balloon includes a balloon, a burner, a hanging basket and four special gas cylinders to fill the tank liquefied gas. The balloon needs to be replaced after 400 hours of use. At present, the most popular AX-7 hot air balloon in China is the AX-7 level. Its volume is 1800 to 2200 cubic meters. After filling the air, the ball has a height of 21 meters, which is equivalent to the height of a seven-story building. It has a maximum diameter of 18 meters, a flight height limit of 15,000 meters, and a maximum load capacity of 620 kilograms. The balloon skin is made of reinforced nylon (some hot air balloons are made of polyester), and although it is light in weight, it is extremely strong and tight.

　　Pilots driving hot air balloons also need to carry instruments such as altimeter, lifting speedometer, thermometer, GPS, walkie-talkie, and ignition gun. The dress is also very particular. You need to wear one-piece cotton clothing and a hat to protect the head and insulate the heat. You also need a pair of thin leather gloves and outdoor sports shoes.

　　The burner is the heart of a hot air balloon and burns compressed gas with energy 150 times larger than that of a general household gas stove. The ignition gun is the fire of the main burner and needs to be kept burning all the time and will not be extinguished even if blown by the wind. In addition, there are two combustion systems on the hot air balloon to prevent failures in the air. A hot air balloon usually carries enough petroleum liquefied gas or propane to last for two hours, but some factors also affect the duration of the flight, such as temperature, wind speed, basket weight (including passengers) and the specific time of flight on the day.

　　Double security guarantee

　　If the burner fails, the flying balloon will act as a parachute and control the descent speed to within 5 meters per second, which is the speed of the parachute landing. Coupled with the buffer protection of rattan hanging basket, it can effectively ensure the safety of passengers and pilots.

　　Ground support

　　Flying hot air balloons requires a group of people to work together, because the work of hot air balloons on the ground is very cumbersome, and it takes at least four people to take off a hot air balloon. First spread the balloon on the ground, then connect it with the hanging basket on the side, use a small blower to blow the wind into the balloon, so that the balloon will expand little by little, and when fully expanded, start ignition. Light the fire to heat the air in the balloon balloon, and the hot air will raise the balloon to a position perpendicular to the hanging basket. Add a few more fires and the balloon can take off.

　　The hot air balloon is also needed to restore the original state of the ground staff. Rent a ground crew recycling vehicle. The ball flies in the sky and the car chases it on the ground. The ground staff drives a truck or minivan and arrives at the landing point in advance. A hot air balloon requires the service of 3-4 ground crew members and ground radio equipment to ensure the safety and success of the flight.